KR20210142473A - Apparatus for preparing positive electrode active material for secondary battery - Google Patents

Abstract

The present invention is to provide an apparatus for preparing a positive electrode active material, capable of resolving the problem of firing temperature varying by position in a firing furnace to achieve uniform physical properties. The present invention includes a firing tube located in a kiln and having a gas inlet at one end and a gas outlet at the other end; a heating element surrounding the outer circumferential surface of the firing tube; and a firing container positioned within the firing tube and containing a positive electrode active material precursor, wherein the firing container includes a first ceramic plate that extends and protrudes from one surface of the firing container facing the gas inlet and a second ceramic plate that extends and protrudes from the other surface of the firing container at a position opposite to the first ceramic plate.

Description

Apparatus for manufacturing a cathode active material for a secondary battery

The present invention relates to an apparatus for manufacturing a cathode active material for a secondary battery.

Recently, with the rapid spread of electronic devices using batteries, such as mobile phones, notebook computers, and electric vehicles, the demand for small, lightweight and relatively high-capacity secondary batteries is rapidly increasing. In particular, a lithium secondary battery has been in the spotlight as a driving power source for a portable device because it is lightweight and has a high energy density. Accordingly, research and development efforts for improving the performance of lithium secondary batteries are being actively conducted.

In a lithium secondary battery, an organic electrolyte or a polymer electrolyte is charged between a positive electrode and a negative electrode made of an active material capable of intercalation and deintercalation of lithium ions, and lithium ions are intercalated/deintercalated from the positive electrode and the negative electrode. Electric energy is produced by a reduction reaction with

A lithium transition metal oxide is used as a cathode active material of the lithium secondary battery. Specifically, lithium cobalt oxide having a high operating voltage and excellent capacity characteristics, lithium nickel oxide having a high reversible capacity of about 200 mAh/g and easy to implement a large-capacity battery, and low heat while maintaining the excellent reversible capacity of the lithium nickel oxide As a method for improving stability, lithium nickel cobalt oxide in which a part of nickel is substituted with cobalt or lithium nickel cobalt metal oxide in which part of nickel is substituted with manganese, cobalt or aluminum, lithium manganese-based oxide with excellent thermal stability and low cost, Lithium iron phosphate excellent in stability is used.

A cathode active material used in a lithium secondary battery is manufactured by putting a precursor for producing a cathode active material and a lithium raw material into a kiln, and sintering with a gas such as oxygen or nitrogen at a high temperature. Maintaining a constant temperature, temperature distribution, and uniformity in the firing process are important in manufacturing a uniform fired product, and local differences in firing temperature occur depending on where the heating element is located in the firing furnace. Even within the lab scale small kiln, there is a temperature difference depending on the location of the heating element. The non-uniformity of the sintering temperature is due to the physical and chemical properties of the sintered cathode active material (e.g., crystal size, particle size, residual lithium content, cation mixing ratio). (cation mixing, etc.), there was a problem in that non-uniform positive electrode active materials having different properties were manufactured in the fired product.

Japanese Patent Laid-Open No. 1999-016572

An object of the present invention is to provide a positive electrode active material manufacturing apparatus capable of manufacturing a positive electrode active material having uniform physical properties by solving the non-uniformity of the firing temperature for each location in a firing furnace when manufacturing a positive electrode active material for a secondary battery.

The present invention is located in the firing furnace, the firing tube having a gas inlet at one end and a gas outlet at the other end; a heating element surrounding the outer circumferential surface of the firing tube; and a firing vessel positioned within the firing tube and containing a cathode active material precursor; wherein the firing vessel includes a first ceramic plate that protrudes from one surface of the firing vessel facing the gas inlet and a second protrudes that extends from the other surface of the firing vessel at a position opposite to the first ceramic plate. Provided is an apparatus for manufacturing a positive active material for a secondary battery in which a ceramic plate is formed.

The apparatus for manufacturing a cathode active material for a secondary battery according to the present invention can manufacture a cathode active material having uniform physical properties by solving the non-uniformity of the firing temperature for each location in the firing furnace to maintain a uniform temperature distribution.

1 is a schematic cross-sectional view of an apparatus for manufacturing a cathode active material according to an embodiment of the present invention.
2 is a view schematically showing a cross-section of a firing vessel according to an embodiment of the present invention and the related art.
3 is a graph showing the temperature change according to the distance in the kiln of Comparative Examples and Examples.

Hereinafter, the present invention will be described in more detail to help the understanding of the present invention. At this time, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor appropriately defines the concept of the term in order to best describe his invention. Based on the principle that it can be done, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

An apparatus for manufacturing a cathode active material for a secondary battery according to the present invention includes: a firing tube positioned in a firing furnace and having a gas inlet at one end and a gas outlet at the other end; a heating element surrounding the outer circumferential surface of the firing tube; and a firing container positioned within the firing tube and containing a cathode active material precursor, wherein the firing container includes a first ceramic plate and the first ceramic plate protruding from one surface of the firing container facing the gas inlet A second ceramic plate that protrudes and extends from the other surface of the firing vessel at a position opposite to the first ceramic plate is formed.

1 is a schematic cross-sectional view of an apparatus for manufacturing a cathode active material according to an embodiment of the present invention. Referring to FIG. 1 , the firing tube 10 is positioned in the firing furnace 100 , and the firing tube 10 has a gas inlet 11 at one end and a gas outlet 12 at the other end. During the firing process, a reaction gas is introduced into the gas inlet 11 and gas is discharged through the gas outlet 12 , and may be a one-way firing furnace.

The shape of the firing tube is not particularly limited, and for example, it may be a cylindrical shape, a square column shape, or the like, and more preferably a cylindrical tube in terms of uniform heat transfer and gas flow. The firing tube may be made of ceramic or quartz.

The outer circumferential surface of the firing tube 10 is surrounded by a heating element 20 , and a firing container 30 containing a cathode active material precursor in the firing tube 10 is located. The heating element 20 can use a heating element known in the art without limitation, for example, SiC, nichrome wire, Kantal (Kantal), super Kantal (Kantal-super), etc. can be used, Considering the firing temperature range of the positive electrode active material, SiC may be more preferably used. For the firing vessel 30 , materials commonly used in the art may be used without limitation, for example, graphite, Al ₂ O ₃ , ZrO ₂ , quartz, or the like may be used.

The firing vessel 30 of the present invention includes a first ceramic plate 31 extending and protruding from one surface of the firing vessel 30 facing the gas inlet 11 and facing the first ceramic plate 31 . A second ceramic plate 32 protruding from the other surface of the firing vessel 30 is formed. As for the first and second ceramic plates 31 and 32 , similarly to the firing vessel 30 , those commonly used as materials of the firing vessel in the art may be used without limitation, for example, graphite, Al _{2 .} O ₃ , ZrO ₂ , quartz, etc. may be used, and may be formed of the same or a different material as that of the firing vessel 30 .

Conventionally, there was a problem that the firing temperature for each location in the firing furnace was not uniform, and in particular, there was a problem that the temperature decreased as it moved away from the heating element. By forming the ceramic plates 31 and 32 , a heat-retaining effect is generated, and thus, a uniform temperature range in the firing container 30 may be obtained.

According to an embodiment of the present invention, the first ceramic plate and the second ceramic plate may have an opening shape through which a reactive gas can move during firing. In the firing process, a reaction gas necessary for the firing reaction, such as oxygen and nitrogen, is fed into the gas inlet 11 and discharged through the gas outlet 12 . For a smooth reaction with the reaction gas, the first and second ceramic plates 31 and 32 may have an opening shape through which the reaction gas can move. The opening shapes of the first ceramic plate and the second ceramic plate are not particularly limited as long as they can move the reactive gas while maintaining the thermal insulation effect, but may have, for example, a lattice opening shape. 2 is a view schematically showing a cross-section of a firing vessel according to an embodiment of the present invention and the related art. Referring to FIG. 2 , the conventional firing vessel does not have a protruding ceramic plate extending from one surface, and in this case, it is difficult to maintain a uniform temperature in the firing vessel due to poor thermal insulation effect. On the other hand, the firing containers according to the first and second embodiments have a ceramic plate protruding from one surface, and have a grid-like opening shape. The shape of the ceramic plate is not particularly limited, but may be, for example, a shape in which a semicircular plate shape is added as shown in FIG. 2 . As in the first and second embodiments of FIG. 2 , since the ceramic plate has an opening shape, it is possible to ensure smooth movement of the injected reactive gas while maintaining a uniform temperature through the thermal insulation effect, so that the firing reactivity is not inhibited. As in the first and second embodiments of FIG. 2 , the aperture ratio of the first and second ceramic plates may be controlled by adjusting shapes such as the size and number of apertures.

Each of the first ceramic plate 31 and the second ceramic plate 32 may have an opening ratio of 30 to 75%, more preferably 40 to 75%, and still more preferably 45 to 60%. When the opening ratios of the first ceramic plate 31 and the second ceramic plate 32 are too low, the movement of the input gas is restricted, and the reactivity between the reaction gas and the fired product is reduced, so that the crystallite size becomes small, or the cation There may be a problem in that the value of cation mixing becomes high, and if the opening ratio is too high, the thermal insulation effect is deteriorated, and the effect of equalizing the temperature in the firing vessel may be greatly reduced.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

[Experimental Example 1: Measurement of temperature change in firing vessel]

As shown in Table 1 below, temperature changes in the firing vessels of Examples 1 to 7 in which the opening ratios of the first and second ceramic plates were adjusted were measured. In addition, the temperature change in the firing vessel of Comparative Example 1 including the conventional firing vessel without the ceramic plate protruding from the firing vessel was measured. Only the inner region of the firing vessel was measured, and the temperature was measured at intervals of 2 cm from the gas inlet side to the gas outlet side. The results are shown in Table 2 and FIG. 3 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Aperture rate (%) 0 5 30 45 60 75 90 Ceramic plate X

Distance (cm) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 0 779.6 779.2 779.2 778.2 777.6 776.3 775.7 774.9 2 779.7 779.5 779.3 778.4 778.1 777.6 777.4 776.8 4 779.8 779.8 779.6 779.4 779.1 778.8 778.7 778.2 6 780.2 780.2 780.2 780.2 780.2 780.2 780.2 780.2 8 780.2 780.2 780.2 780.2 780.2 780.2 780.2 780.2 10 780.1 780.1 780.1 780.1 780.1 780.1 780.1 780.1 12 780.0 780.0 779.6 779.5 779.1 778.8 778.7 778.3 14 779.8 779.7 779.5 778.9 778.5 777.8 777.7 777.0 16 779.7 779.4 779.4 778.4 777.5 776.5 776.0 775.3

Referring to Table 2 and FIG. 3 , in Comparative Example 1 having a firing vessel in which a ceramic plate is not formed, the temperature was the most non-uniform. It can be confirmed that the temperature equalization effect of Examples 1 to 6 in which the opening ratio of the ceramic plate is 75% or less is excellent.

[Experimental Example 2: Confirmation of firing reactivity]

As shown in Table 1, cation mixing values were measured in order to confirm the firing reactivity of the positive active materials prepared using the firing containers of Examples 1 to 7 in which the opening ratios of the first and second ceramic plates were adjusted. . In addition, the cation mixing value of the positive active material prepared by using the firing vessel of Comparative Example 1 including the conventional firing vessel not having the ceramic plate protruding from the firing vessel was measured. The numerical value of the cation mixing value was obtained through the TOPAS analysis method after measuring the X-ray diffraction of the positive electrode active material. The results are shown in Table 3 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 cation mixing (%) 3.6 2.8 1.9 1.8 2.0 2.7 3.1 3.5

Referring to Table 3, in the case of Comparative Example 1 having a firing vessel in which a ceramic plate is not formed or Example 1 in which the opening ratio of the ceramic plate is 0%, the firing reactivity is very low and the cation mixing value is high. appeared can be seen. On the other hand, in the case of Examples 3 to 6, in which the opening ratio of the ceramic plate was 30% to 75%, the firing reactivity was improved and cation mixing was low, and in particular, Examples 3 to 5 were cation mixing (cation mixing). ) was significantly lower.

100: kiln
10: firing tube
11: gas inlet
12: gas outlet
20: heating element
30: firing vessel
31, 32: first ceramic plate, second ceramic plate

Claims (6)

a firing tube positioned in the firing furnace and having a gas inlet at one end and a gas outlet at the other end;
a heating element surrounding the outer circumferential surface of the firing tube; and
a firing container positioned within the firing tube and containing a cathode active material precursor; includes,
The firing vessel may include a secondary having a first ceramic plate extending and protruding from one surface of the firing vessel facing the gas inlet and a second ceramic plate extending from the other surface of the firing vessel at a position facing the first ceramic plate and protruding An apparatus for manufacturing a cathode active material for a battery.
According to claim 1,
The first ceramic plate and the second ceramic plate are an apparatus for manufacturing a cathode active material for a secondary battery having an opening shape through which a reactive gas can move during sintering.
3. The method of claim 2,
The first ceramic plate and the second ceramic plate are an apparatus for manufacturing a cathode active material for a secondary battery having an opening shape in the form of a lattice.
3. The method of claim 2,
The first ceramic plate and the second ceramic plate have an aperture ratio of 30 to 75%.
5. The method of claim 4,
The first ceramic plate and the second ceramic plate have an aperture ratio of 45 to 60%.
According to claim 1,
The first ceramic plate and the second ceramic plate are at least one selected from the group consisting _{of graphite, Al 2} O ₃ , ZrO _{2 and quartz.}

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